1. Field of the Invention
This invention relates to a frame interline transfer (FIT) type CCD imager in which signal charges are transferred from a plurality of photosensors to vertical transfer units so as to be transferred via a storage section to a horizontal transfer unit,
2. Description of the Prior Art
The FIT type CCD imager is a solid state imager mainly comprised of an imaging section which is composed of photosensors arrayed in a matrix configuration, having vertical columns and horizontal rows, and vertical transfer units, a storage unit for transiently storing electrical charges, and a horizontal transfer unit for transferring the electrical charges on the line-by-line basis. Such technology is disclosed in, for example, the Japanese Patent Laid Open Publication No. 56-8966(1981).
With such a FIT type CCD imager, after the signal charges in the photosensors are read out into the vertical transfer units, during a vertical blanking period, the signal charges are transferred at a high transfer rate corresponding to the number of register stages in the storage section. The signal charges thus transferred by such transfer at the high transfer rate to the storage section are output by the horizontal transfer unit at an output buffer on a line-by-line basis.
However, when excess carriers are generated at the photosensors during signal charge transfer from the vertical transfer units to the storage section at the high transfer rate, the charges are caused to overflow from the photosensors into the vertical transfer units to produce so-called blooming. As a result, white tinted vertical streaks are produced on the monitor screen surface.